Tamworth's main water supply crept over the milestone level on Thursday, according to data from Water NSW.

Tamworth Regional Council's (TRC) drought management plan indicates Tamworth, Moonbi and Kootingal could drop back from Level 5 to Level 4 restrictions when the water supply hits that trigger point of a quarter full.

Now, that trigger point has just been reached, but the dam level could drop again.

TRC still has to make a decision and previously warned residents to wait for official notification of any changes to water restrictions before changing their water use.

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If TRC makes the call to ease Level 5 restrictions back to Level 4, the target for water users in Tamworth would be raised from 150 litres per day to 200 litres per day.

Rainfall during the past month has seen Chaffey Dam surge in capacity from about 15 per cent on July 20 to 25 per cent on August 20, according to Water NSW data.

Council is not taking any water from the dam for the city's needs, instead sourcing it mostly from the full Dungowan Dam.

Environmental flows continue to be released at a rate of 3ML each day. It is understood the rise to 25 per cent capacity doesn't change that number.